Medical and dietary therapy for kidney stone prevention

Current Dietary and Medical Prevention of Renal Calcium Oxalate Stones

Kidney stones refer to abnormal crystal formation that occurs in the kidney. Among a variety of components of kidney stones, calcium oxalate (CaOx) is the most common type. Despite many efforts to investigate the pathogenesis of CaOx stones, the pathogenesis remains an issue of debate. With high occurrence and recurrence, individuals with stone formation are prone to frequently consult a doctor and to be hospitalized, and the treatment of kidney stones poses a heavy burden on the patients. Concerns should be focused not only on treatment but also on prevention. Herein, we reviewed the studies on prevention methods of CaOx stones through diet, lifestyle, and medication extending until the current time frame. As hyperoxaluria is the most common metabolic disorder among CaOx stone formations, we also included several studies on the treatment and prevention of hyperoxaluria. Our objective was to outline the effective methods to prevent renal CaOx stone formation.

Gut microbiome-metabolites axis: A friend or foe to colorectal cancer progression

An expanding corpus of research robustly substantiates the complex interrelation between gut microbiota and the onset, progression, and metastasis of colorectal cancer. Investigations in both animal models and human subjects have consistently underscored the role of gut bacteria in a variety of metabolic activities, driven by dietary intake. These activities include amino acid metabolism, carbohydrate fermentation, and the generation and regulation of bile acids. These metabolic derivatives, in turn, have been identified as significant contributors to the progression of colorectal cancer. This thorough review meticulously explores the dynamic interaction between gut bacteria and metabolites derived from the breakdown of amino acids, fatty acid metabolism, and bile acid synthesis. Notably, bile acids have been recognized for their potential carcinogenic properties, which may expedite tumor development. Extensive research has revealed a reciprocal influence of gut microbiota on the intricate spectrum of colorectal cancer pathologies. Furthermore, strategies to modulate gut microbiota, such as dietary modifications or probiotic supplementation, may offer promising avenues for both the prevention and adjunctive treatment of colorectal cancer. Nevertheless, additional research is imperative to corroborate these findings and enhance our comprehension of the underlying mechanisms in colorectal cancer development.

Utilization of barley and parsley for the management of urolithiasis among the Saudi Arabian population

Objective

To determine the utilization of barley and parsley for managing urolithiasis among the Saudi Arabian population.

Methods

This is a prospective cross-sectional survey-based study. The survey comprised questions about the use of barley, parsley, and other therapies for managing urolithiasis. A WhatsApp® message with the link to the study survey was sent out to family, friends, patients, and other acquaintances residing in the Kingdom of Saudi Arabia (KSA).

Results

A total of 1014 respondents completed the survey, of which 44.8% indicated that they utilized barley, 38.3% stated that they used parsley, and 4.2% indicated that they utilized other non-medical remedies to treat or prevent kidney stones. In contrast, only 29.5% stated that they utilized potassium citrate and/or magnesium citrate, and only 14.4% indicated that they consumed greater amounts of water to treat or prevent kidney stones.

Conclusion

Our study findings indicate that among the Saudi Arabian population, non-conventional therapies such as barley and parsley are more commonly utilized for managing urolithiasis rather than established therapies such as increasing water intake and the use of potassium-citrate/ magnesium-citrate. There is a need to conduct large-scale clinical studies to evaluate the efficacy and safety of barley, parsley, and other non-conventional therapies for treating urolithiasis.

Association of dietary carotenoid intake with the prevalence kidney stones among the general adult population

PURPOSE

This study was to examine whether higher dietary carotenoid intake levels were associated with a lower prevalence of kidney stones.

MATERIALS AND METHODS

This study analyzed data from 2007 to 2018 National Health and Nutrition Examination Survey (NHANES) project. Dietary carotenoid intake (α-carotene, β-carotene, β-cryptoxanthin, lycopene, and lutein/zeaxanthin) was assessed using two 24-h dietary recall interviews. Multiple logistic regression and weighted quantile sum (WQS) regression were applied to examine the associations between five dietary carotenoids alone, compounds, and the prevalence of kidney stones. The dose-response relationships were analyzed by restricted cubic spline regression.

RESULTS

A total of 30,444 adults (2909 participants with kidney stones) were included in the analysis. The mean age of the participants was 49.95 years and 49.2% of the participants were male. Compared with the first quartile, the fourth quartile of α-carotene (odds ratio [OR] = 0.82 [0.73-0.92]), β-carotene (OR = 0.79 [0.70-0.89]), β-cryptoxanthin (OR = 0.88 [0.79-0.99]), and lutein/zeaxanthin (OR = 0.80 [0.71-0.91]) were significantly and inversely associated with the prevalence of kidney stones after adjusting for confounders. The dose-response analysis showed a linear relationship between five dietary carotenoid intake levels and the prevalence of kidney stones. Further WQS analysis revealed that the combination of all five dietary carotenoids was negatively associated with and the prevalence of kidney stones, with the largest effect coming from β-carotene (weight = 0.538).

CONCLUSION

Our findings indicated that higher dietary carotenoid intake levels were associated with decreased prevalence of kidney stones, and increasing the intake of foods rich in β-carotene may prevent the development of kidney stones.

Consideration of Comparing Empirical and Evidence-Based Knowledge on Nephrology in the Example of Ahi Çelebi's Fifteenth Century Turkish Treatise on the Urinary Calculus

The objective of the study is to discuss the question, "how did physicians come to grasp some facts in the absence of scientific experimentation and medical technology?" within the framework of examples from Ahı? Ahmed Çelebi's fifteenth century Turkish treatise on the urinary calculus. Çelebi's monograph on the urinary calculus in the kidneys and the bladder written in Turkish in Arabic alphabet is transliterated and studied within the framework of the medical theory of the period. The sample information for this study was randomly chosen. Examples of epidemiological information, diets against urinary calculus formation, diagnoses of kidney and urinary bladder calculi, and symptomatic therapies noted in Çelebi's treatise are discussed, with results briefly compared with today's data. The study of Çelebi's treatise shows that it was possible to reach some medical facts with the methods of the period.

Case report: disease mechanisms and medical management of calcium nephrolithiasis in rheumatologic diseases

Background

Nephrolithiasis as a feature of rheumatologic diseases is under recognized. Understanding presenting features, diagnostic testing is crucial to proper management.

Case presentation

A 32 year old woman with a history of recurrent complicated nephrolithiasis presented to a rheumatologist for a several month history of fatigue, dry eyes, dry mouth, arthralgias. She had a positive double-stranded DNA, positive SSA and SSB antibodies. She was diagnosed with Systemic Lupus erythematosus (SLE) and Sjogren's syndrome and was started on mycophenalate mofetil. Of relevance was a visit to her local emergency room 4 years earlier with profound weakness with unexplained marked hypokalemia and a non-anion gap metabolic acidosis. Approximately one year after that episode she developed flank pain and nephrocalcinosis. She had multiple issues over the ensuing years with stones and infections on both sides. Interventions included extracorporeal shockwave lithotripsy as well as open lithotomy and eventual auto-transplantation of left kidney for recurrent ureteric stenosis. 24 h stone profile revealed marked hypocitraturia, normal urine calcium, normal urine oxalate and uric acid. She was treated with potassium citrate. Mycophenolate was eventually stopped due to recurrent urinary tract infections and she was started on Belimumab. Because of recurrent SLE flares, treatment was changed to Rituximab (every 6 months) with clinical and serologic improvement. Her kidney stone frequency gradually improved and no further interventions needed although she continued to require citrate repletion for hypocitraturia.

Conclusions

Nephrolithiasis can be a prominent and even presenting feature in Sjogrens syndrome as well as other rheumatologic diseases. Prompt recognition and understanding disease mechanisms is important for best therapeutic interventions for kidney stone prevention as well as treatment of underlying bone mineral disease.

Effects of lemon-tomato juice consumption on crystal formation in the urine of patients with calcium oxalate stones: A randomized crossover clinical trial

Background

Dietary supplementation with citrate-containing juices may serve as an effective alternative to potassium citrate therapy for preventing calcium oxalate stone recurrence. This study was performed to evaluate whether consumption of lemon-tomato juice can decrease the tendency for stone formation in the urine of calcium oxalate stone formers.

Materials and methods

The study was conducted as a prospective interventional randomized crossover clinical trial with a repeated-measures design. Twenty-two patients with calcium oxalate stones and no metabolic abnormalities in the urine treated with lithotripsy at a tertiary care center from August 2017 to July 2018 were recruited. After a 14-hour overnight fasting, urine samples were collected after the patients consumed either milk only or milk and lemon-tomato juice. Their urine was tested for multiple parameters, including urine pH, specific gravity, calcium-creatinine ratio, and supersaturation with sodium oxalate, followed by optical density measurement via spectrophotometry.

Results

There were no significant differences in the background characteristics between the 2 groups. The optical density of the urine samples obtained after consumption of milk only was significantly higher than that after consumption of milk and lemon-tomato juice (mean = 0.131 for milk only vs. 0.053 for milk and lemon-tomato juice, p < 0.001). The urine calcium-creatinine ratio was similar between the groups (mean = 0.141 for milk only vs. 0.076 for milk and lemon-tomato juice, p = 0.019).

Conclusions

The addition of lemon-tomato juice as a source of citrate in the diet significantly decreases the established risk factors for calcium oxalate stone formation in patients. This study was prospectively registered at CTRI under number CTRI/2017/04/008312 on April 7, 2017.

Clinical Characteristics and In Silico Analysis of Cystinuria Caused by a Novel SLC3A1 Mutation

Cystinuria is a genetically inherited disorder of renal and intestinal transport, featured as a high concentration of cystine in the urine. Cumulative cystine in urine would cause the formation of kidney stones, which further leads to renal colic and dysfunction. Gene screens have found that mutations in SLC3A1 or SLC7A9 gene are responsible for most cases of cystinuria, for encoding defective cystine transporters. Here, we presented the genotypic and phenotypic characteristics of one unique case of a three-generation Chinese family. The proband developed severe urolithiasis combined with renal damage. The radiography and computed tomography (CT) scan showed calculus in the left pelvic kidney. Postoperative stone analysis revealed that the stones were mainly composed of cystine. Therefore, to explore its pathogenesis, next-generation Whole Exome Sequencing (WES) and Sanger sequencing identify the proband mutated gene of the proband’s family. In this article, we reported novel compound heterozygous mutations (c.818G>A and c.1011G>A) of the SLC3A1 gene in a 5-year-old child suffering from a cystine stone from a three-generation family. Bioinformatic analysis was used to predict the pathogenicity and conservation of the target mutation. Conservative sequence and evolutionary conservation analysis indicated that cystine273 and proline337 were highly conserved among species, and both mutations listed here (Cys273Tyr and Pro337Pro) were pathogenic. To conclude, our study expands the phenotypic and genotypic spectrum of SLC3A1 and indicates that genetic screening should be considered in the clinic to provide more effective and precise treatment for cystinuria.

Oxalate-induced apoptosis through ERS-ROS-NF-κB signalling pathway in renal tubular epithelial cell

Background

Kidney stones are composed of approximately 70–80% calcium oxalate. However, the exact mechanism of formation of calcium oxalate kidney stones remains unclear. In this study, we investigated the roles of endoplasmic reticulum stress (ERS), reactive oxygen species (ROS), and the NF-κB signalling pathway in the pathogenesis of oxalate-induced renal tubular epithelial cell injury and its possible molecular mechanisms.

Methods

We established a model to evaluate the formation of kidney stones by intraperitoneal injection of glyoxylic acid solution into mice and assessed cell morphology, apoptosis, and the expression levels of ERS, ROS, and NF-κB signalling pathway-related proteins in mouse renal tissues. Next, we treated HK-2 cells with potassium oxalate to construct a renal tubular epithelial cell injury model. We detected the changes in autophagy, apoptosis, and mitochondrial membrane potential and investigated the ultrastructure of the cells by transmission electron microscopy. Western blotting revealed the expression levels of apoptosis and autophagy proteins; mitochondrial structural and functional proteins; and ERS, ROS, and NF-κB (p65) proteins. Lastly, we studied the downregulation of NF-κB activity in HK-2 cells by lentivirus interference and confirmed the interaction between the NF-κB signalling and ERS/ROS pathways.

Results

We observed swelling of renal tissues, increased apoptosis of renal tubular epithelial cells, and activation of the ERS, ROS, and NF-κB signalling pathways in the oxalate group. We found that oxalate induced autophagy, apoptosis, and mitochondrial damage in HK-2 cells and activated the ERS/ROS/NF-κB pathways. Interestingly, when the NF-κB signalling pathway was inhibited, the ERS/ROS pathway was also inhibited.

Conclusion

Oxalate induces HK-2 cell injury through the interaction between the NF-κB signalling and ERS/ROS pathways.

Dietary Risk Factors for Incident and Recurrent Symptomatic Kidney Stones

OBJECTIVE

To compare dietary factors between incident symptomatic stone formers and controls, and among the incident stone formers, to determine whether dietary factors were predictive of symptomatic recurrence.

PATIENTS AND METHODS

We prospectively recruited 411 local incident symptomatic kidney stone formers (medical record validated) and 384 controls who were seen at Mayo Clinic in Minnesota or Florida between January 1, 2009, and August 31, 2018. Dietary factors were based on a Viocare, Inc, food frequency questionnaire administered during a baseline in-person study visit. Logistic regression compared dietary risk factors between incident symptomatic stone formers and controls. Incident stone formers were followed up for validated symptomatic recurrence in the medical record. Cox proportional hazards models estimated risk of symptomatic recurrence with dietary factors. Analyses adjusted for fluid intake, energy intake, and nondietary risk factors.

RESULTS

In fully adjusted analyses, lower dietary calcium, potassium, caffeine, phytate, and fluid intake were all associated with a higher odds of an incident symptomatic kidney stone. Among incident stone formers, 73 experienced symptomatic recurrence during a median 4.1 years of follow-up. Adjusting for body mass index, fluid intake, and energy intake, lower dietary calcium and lower potassium intake were predictive of symptomatic kidney stone recurrence. With further adjustment for nondietary risk factors, lower dietary calcium intake remained a predictor of recurrence, but lower potassium intake only remained a predictor of recurrence among those not taking thiazide diuretics or calcium supplements.

CONCLUSION

Enriching diets in stone formers with foods high in calcium and potassium may help prevent recurrent symptomatic kidney stones.

Shedding light on pharmacists' knowledge of kidney stones' etiology and treatment

Background

The recurring nature of kidney stones (KS) makes it difficult to control and treat. Patients' education plays a part in reducing disease recurrence. Pharmacists participate in the healthcare services through educating patients with kidney stones about KS preventive measures and medications that greatly reduce the disease frequency and the treatment cost. Insufficient pharmacists' knowledge may affect the services' quality and result in misuse of KS medications.

Objectives

To evaluate the pharmacists' level of knowledge to provide adequate information about KS preventive measures, medications, and treatments for patients with kidney stones in Jordan.

Methods

An online descriptive survey was distributed to pharmacists to assess their knowledge about KS causes, prevention, and treatment. The results were analyzed using the SPSS software.

Results

There were 393 pharmacists participated in this study. Pharmacists demonstrated an overall intermediate level of knowledge about KS. They showed an excellent level of knowledge regarding KS types and etiology, an intermediate level of knowledge about KS preventive measures and treatment, and poor knowledge about home remedies and drugs that promote KS formation.

Conclusion

Pharmacists knowledge about KS management through diet and medications need to be improved. This could be through focusing on pharmacists' training for the effective implementation of knowledge in the clinical practice. Adopting guidelines by pharmacists may reduce the risk of KS recurrence and provide pharmacist-led patient education about KS management in hospitals and community pharmacies.

Association of meteorological factors and ambient air pollution on medical care utilization for urolithiasis: a population-based time-series study

BACKGROUND

To identify the association of meteorological factors/ambient air pollutants with medical care utilization for urolithiasis and estimate the effect size/time lags.

METHODS

This is a population-based time-series analysis of 300,000 urolithiasis cases from eight large metropolitan areas in Korea. Seventeen meteorological factors and ambient air pollutants were measured daily during 2002-2017 for each metropolis. Data on daily medical utilization owing to urolithiasis were collected. A generalized additive model was used while factoring in the nonlinear relationship between meteorological factors/ambient air pollutants and urolithiasis and a time lag of ≤10 days. A multivariate analysis was performed. Backward elimination with an Akaike information criterion was used for fitting the multivariate model.

RESULTS

Urolithiasis was significantly associated with average temperature, diurnal temperature range, sunshine duration, particulate matter (PM) ≤2.5 μm, and carbon monoxide (CO) levels. The incidence of ureteral stones was positively correlated with average temperature, PM ≤2.5 μm level, and CO level (time lags 0-9, 2-4, and 0-9 days, respectively). The incidence of renal stones was positively correlated with PM ≤2.5 μm and CO levels (time lags 2-4 and 0-9 days, respectively). PM ≤2.5 μm (0.05 and 0.07% per 10 μg/m³⁾ and CO (2.05 and 2.25% per 0.1 ppm) conferred the highest excess risk on ureteral and renal stones.

CONCLUSIONS

Urolithiasis is affected by various meteorological factors and ambient air pollutants, PM ≤2.5 μm, and CO levels may be novel potential risk factors for this condition.

The Relationship between Modern Fad Diets and Kidney Stone Disease: A Systematic Review of Literature

Objectives: Kidney stone disease (KSD) has a strong association with diet metabolic syndrome. This review aims at exploring the lithogenic risk posed by the current most popular diets. Our approach was to search for the effect of each diet type on the major urinary risk factors, to try to draw conclusions regarding the association of a specific diet type and KSD. Methods: This systematic review searched for the available literature exploring the association between the existing popular fad diets and KSD. Articles in English, French and Spanish were included, without restriction of the search period with the final search done in August 2021. Results: Total number of studies and studies for each diet type was as follows: 22 articles for the low carbohydrate diet, 20 articles for high protein diets, 26 articles for vegetarian and vegan diets. There exists a substantial variability in different low carbohydrate and high protein diets, and considerable overlap between modern popular fad diets. High carbohydrate intake might increase urine uric acid, calcium and oxalate levels. High protein diets increase urine calcium and uric acid and lower urine pH and citrate. Consumption of fruits and vegetables increases the urinary volume and urinary citrate. In vegan diets, sufficient daily calcium intake is important to avoid possible secondary hyperoxaluria. Conclusions: Few studies evaluated the direct relationship between modern fad diets and KSD. In general, the reduction of carbohydrate in the diet, and counterbalancing protein rich diets with sufficient intake of fruits and vegetables, seem to play a protective role against KSD formation. Maintaining sufficient calcium intake in vegan and vegetarian diets is important. Additional research is needed to directly evaluate the link between KSD and each diet type.

Effect of Vitamin B2-Deficient Diet on Hydroxyproline- or Obesity-Induced Hyperoxaluria in Mice

SCOPE

Hyperoxaluria is a major cause of kidney stone disease. Around half of the oxalate in mammals is supplied from the diet and the other half is endogenously synthesized from glyoxylate. Reduction of hepatic glycolate oxidase (GO) activity is one approach to reduce endogenous production of oxalate. However, there are currently few effective dietary approaches to reduce hepatic GO activity.

METHODS AND RESULTS

In the present study, it is investigated whether restriction of dietary vitamin B2 (VB2) can reduce hepatic GO activity and oxalate excretion in mice with hyperoxaluria induce by hydroxyproline (Hyp) or obesity. It is found that VB2 restriction significantly reduces hepatic GO activity in both the Hyp- and obesity-induced model of hyperoxaluria in mice. However, VB2 restriction reduces urinary oxalate excretion only in the Hyp-treated mice and not the obese mice. This difference could be due to the contribution of endogenous oxalate production that manifests as increased hepatic GO activity in Hyp-treated mice but not obese mice.

CONCLUSION

Together these results suggest that VB2 restriction could be a new dietary approach to improve hyperoxaluria when endogenous production of oxalate is increased.

A study of crystalluria: effectiveness of including hygienic-dietary recommendations in laboratory reports

Objectives

To assess the effectiveness of incorporating hygienic-dietary recommendations in laboratory reports in reducing the incidence of renal colic (RC). A study was performed to compare the incidence of RC in two groups of patients who had suffered at least a crystalluria event associated with the risk of urolithiasis. Recommendations were only incorporated in the laboratory reports of one group.

Methods

A retrospective observational study. The study sample was composed of patients who had at least an episode of crystalluria associated with a higher risk of urolithiasis. The laboratory reports of patients in Group A (n=1,115), treated in 2017, did not include any hygienic-dietary recommendations, whereas patients in Group B (n=1,692), treated in 2018, received hygienic-dietary recommendations through their laboratory reports. χ² and Mann-Whitney U test were used to assess differences based on sex, age, and type of urinary crystals.

Results

The incidence of RC was 2.02 times higher in group A (2.24%) than in group B (1.12%). No significant differences were observed in the incidence of RC based on the type of urinary crystal. The incidence of RC was substantially higher in patients who suffered at least an event of crystalluria associated with a higher risk for urolithiasis as compared to the general population during the same period (0.46%, consistently with the incidence rates reported in the literature).

Conclusions

The incorporation of messages alerting on the risk of urolithiasis and the inclusion of hygienic-dietary recommendations in laboratory reports may be useful for reducing the incidence of RC.

Citric acid from Aspergillus niger: a comprehensive overview

Microbial citric acid has high economic importance and widely used in beverage, food, detergents, cosmetics and pharmaceutical industries. The filamentous fungus Aspergillus niger is a work horse and important cell factory in industry for the production of citric acid. Although in-depth literatures and reviews have been published to explain the biochemistry, biotechnology and genetic engineering study of citric acid production by Aspergillus niger separately but the present review compiled, all the aspects with upto date brief summary of the subject describing microorganisms, substrates and their pre-treatment, screening, fermentation techniques, metabolic engineering, biochemistry, product recovery and numerous biotechnological application of citric acid for simple understanding of microbial citric acid production. The availability of genome sequence of this organism has facilitated numerous studies in gene function, gene regulation, primary and secondary metabolism. An attempt has been also made to address the molecular mechanisms and application of recent advanced techniques such as CRISPR/Cas9 systems in enhancement of citric acid production.

Oxalate Content and Antioxidant Activity of Different Ethnic Foods

OBJECTIVE

There is not enough information on the classification of oxalate content in several foods, particularly in ethnic foods, to recommend their consumption in subjects with urolithiasis (UL). The objective of the present study was to generate reliable information on the oxalate content and antioxidant activity in different foods and classify them by very low, low, medium, high and very high oxalate content and antioxidant activity.

METHODS

The oxalate content of 109 foods including ethnic foods was assessed by an enzymatic assay, and the antioxidant activity was measured by the oxygen radical absorbance capacity to determine the oxalate/antioxidant activity ratio. Oxalate consumption was then evaluated in 400 subjects with overweight and obesity using 24-h dietary recalls.

RESULTS

The main foods with high oxalate content were raw spinach, huanzontle, purslane, chard, almond, and toasted and sweetened roasted amaranth. The highest antioxidant activity was found in strawberries, all types of chocolates, roselle, morita peppers, and pinolillo. Subjects with overweight or obesity exceed the dietary oxalate daily intake recommendation.

CONCLUSIONS

The classification of foods by their oxalate content and antioxidant activity will be very useful to generate nutritional recommendation in different diseases, mainly UL.

Reduction of ureteral stent encrustation by modulating the urine pH and inhibiting the crystal film with a new oral composition: a multicenter, placebo controlled, double blind, randomized clinical trial

BACKGROUND

Encrustation of ureteral double J stents is a common complication that may affect its removal. The aim of the proposed study is to evaluate the efficacy and safety of a new oral composition to prevent double J stent encrustation in indwelling times up to 8 weeks.

METHODS

A double-blinded, multicenter, placebo-controlled trial was conducted with 105 patients with indwelling double J stents enrolled across 9 public hospitals in Spain. The patients were randomly assigned (1:1) into intervention (53 patients) or placebo (52 patients) groups for 3 to 8 weeks and both groups self-monitored daily their morning urine pH levels. The primary outcome of analysis was the degree of stent ends encrustation, defined by a 4-point score (0 - none; 3 - global encrustation) using macroscopic and electron microscopy analysis of crystals, after 3 to 8-w indwelling period. Score was exponentially transformed according to calcium levels. Secondary endpoints included urine pH decrease, stent removal, and incidence of adverse events.

RESULTS

The intervention group benefits from a lower global encrustation rate of stent ends than placebo group (1% vs 8.2%; p < 0.018). Mean encrustation score was 85.12 (274.5) in the placebo group and 18.91 (102.27) in the intervention group (p < 0.025). Considering the secondary end points, treated patients reported greater urine pH decreases (p = 0.002). No differences in the incidence of adverse events were identified between the groups.

CONCLUSIONS

Our data suggest that the use of this new oral composition is beneficial in the context of ureteral double J indwelling by decreasing mean, as well as global encrustation.

TRIAL REGISTRATION

This trial was registered at www.clinicaltrials.gov under the name "Combined Use of a Medical Device and a Dietary Complement in Patient Urinary pH Control in Patients With an Implanted Double J Stent" with date 2nd November 2017, code NCT03343275, and URL.

Update on cystine stones: current and future concepts in treatment

Cystine stones are relatively uncommon compared with other stone compositions, constituting just 1% to 2% of adult urinary tract stone diseases, and accounting for up to 10% of pediatric stone diseases. Two responsible genes of cystinuria have been identified, the SLC3A1 and the SLC7A9. Cystinuria is diagnosed by family history, stone analysis, or by measurement of urine cystine excretion. Current treatments for cystinuria include increased fluid intake to increase cystine solubility by maintaining daily urine volume of greater than 3 Liter (L). Limiting sodium and protein intake can decrease cystine excretion. When conservative therapy fails, then pharmacologic therapy may be effective. Alkaline urine pH in the 7.0-7.5 range will reduce cystine solubility and can be achieved by the addition of alkali therapy. If these measures fail, cystine-binding thiol drugs such as tiopronin and D-penicillamine are considered. These compounds bind cysteine and prevent the formation of less soluble cystine. These drugs, however, have poor patient compliance due to adverse effects. Captopril can be useful in the treatment of cystine stones but the drug has not been tested in rigorous clinical trials. Novel potential therapies such as alpha-lipoic acid and crystal growth inhibitors (L-cystine dimethyl ester (L-CDME) and L-cystine methyl ester (L-CME)) were developed and tested in animals. Those therapies showed promising results. Compliance with treatment was associated with a lower rate of cystine stone formation.

Risk of Kidney Stones: Influence of Dietary Factors, Dietary Patterns, and Vegetarian-Vegan Diets

Nephrolithiasis is a common medical condition influenced by multiple environmental factors, including diet. Since nutritional habits play a relevant role in the genesis and recurrence of kidney stones disease, dietary manipulation has become a fundamental tool for the medical management of nephrolithiasis. Dietary advice aims to reduce the majority of lithogenic risk factors, reducing the supersaturation of urine, mainly for calcium oxalate, calcium phosphate, and uric acid. For this purpose, current guidelines recommend increasing fluid intake, maintaining a balanced calcium intake, reducing dietary intake of sodium and animal proteins, and increasing intake of fruits and fibers. In this review, we analyzed the effects of each dietary factor on nephrolithiasis incidence and recurrence rate. Available scientific evidence agrees on the harmful effects of high meat/animal protein intake and low calcium diets, whereas high content of fruits and vegetables associated with a balanced intake of low-fat dairy products carries the lowest risk for incident kidney stones. Furthermore, a balanced vegetarian diet with dairy products seems to be the most protective diet for kidney stone patients. Since no study prospectively examined the effects of vegan diets on nephrolithiasis risk factors, more scientific work should be made to define the best diet for different kidney stone phenotypes.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Automatic detection of calcium phosphate deposit plugs at the terminal ends of kidney tubules

Kidney stones are a common urologic condition with a high amount of recurrence. Recurrence depends on a multitude of factors the incidence of precursors to kidney stones, plugs, and plaques. One method of characterising the stone precursors is endoscopic assessment, though it is manual and time-consuming. Deep learning has become a popular technique for semantic segmentation because of the high accuracy that has been demonstrated. The present Letter examined the efficacy of deep learning to segment the renal papilla, plaque, and plugs. A U-Net model with ResNet-34 encoder was tested; the Letter examined dropout (to avoid overtraining) and two different loss functions (to address the class imbalance problem. The models were then trained in 1666 images and tested on 185 images. The Jaccard-cross-entropy loss function was more effective than the focal loss function. The model with the dropout rate 0.4 was found to be more effective due to its generalisability. The model was largely successful at delineating the papilla. The model was able to correctly detect the plaques and plugs; however, small plaques were challenging. Deep learning was found to be applicable for segmentation of an endoscopic image for the papilla, plaque, and plug, with room for improvement.

Patient's perception of kidney stone prevention within the emergency department and its adherence factors: a single institution study

BACKGROUND

No known data in the literature assessing practice of kidney stone prevention in the emergency department (ED) is available.

OBJECTIVES

Assess patient perception and compliance to kidney stone prevention given within the emergency department. It also indirectly detects the attitude and practice patterns of primary care providers in kidney stone prevention.

MATERIALS AND METHODS

This is a qualitative study done in a single institution from January 2018 to January 2019 that includes 99 patients that were diagnosed with kidney or ureteral stone in ED and were discharged home, all of them where stone formers. They were asked to fill a self- administered questionnaire when they are able to read, or interviewed by the resident within the ED when they are unable to read.

RESULTS

The majority of patients (68%) did not receive any instructions about kidney stones prevention within the ED. Most of patients who follow instructions if it was given were educated (90%), had an insurance coverage (85%), and had an income higher than $1000 per month (76%), (p < 0.05). Seventy one percents of patients believe in the effectiveness of stone prevention if it was provided and most of them are interested in learning about these preventive strategies (82%). Reasons for not following the instructions about kidney stones prevention measures were the cost (53.1%) following by the lack of explanation by ED physicians (18.8%). The majority of patients (62.6%) prefer to receive kidney stones prevention measures from urologists.

CONCLUSION

Most of patients in our institute did not receive kidney stones prevention measures in ED despite that they declared their interest in following these measures. Most of the time they did not adhere to those measures due to socioeconomic factors and lack of clarifications. If these instructions were given within the ED, it could lead to an acceptable compliance rate.

Which Diet for Calcium Stone Patients: A Real-World Approach to Preventive Care

Kidney stone disease should be viewed as a systemic disorder, associated with or predictive of hypertension, insulin resistance, chronic kidney disease and cardiovascular damage. Dietary and lifestyle changes represent an important strategy for the prevention of kidney stone recurrences and cardiovascular damage. A full screening of risk factors for kidney stones and for cardiovascular damage should be recommended in all cases of calcium kidney stone disease, yet it is rarely performed outside of stone specialist clinics. Many patients have a history of kidney stone disease while lacking a satisfactory metabolic profile. Nonetheless, in a real-world clinical practice a rational management of kidney stone patients is still possible. Different scenarios, with different types of dietary approaches based on diagnosis accuracy level can be envisaged. The aim of this review is to give patient-tailored dietary suggestions whatever the level of clinical and biochemistry evaluation. This can help to deliver a useful recommendation, while avoiding excessive dietary restrictions especially when they are not based on a specific diagnosis, and therefore potentially useless or even harmful. We focused our attention on calcium stones and the different scenarios we may find in the daily clinical practice, including the case of patients who reported renal colic episodes and/or passed stones with no information on stone composition, urinary risk factors or metabolic cardiovascular risk factors; or the case of patients with partial and incomplete information; or the case of patients with full information on stone composition, urinary risk factors and metabolic cardiovascular profile.

Outcomes and Long-term Follow-up of Patients with Cystine Stones: a Systematic Review

PURPOSE OF REVIEW

Cystine stone patients can be difficult to manage with frequent recurrences. We performed a systematic review with a view to assessing interventions, compliance and their long-term outcomes.

RECENT FINDINGS

Ten retrospective observational studies (253 patients) assessed the outcomes and long-term follow-up of cystine stone patients. The mean length of follow-up was 9.6 years (range 3.5-21.8 years). The overall mean number of surgical procedures/patient was 5.7 (range 2-9.8/patient) with the overall mean number of surgical procedures/patient/year at 0.59 (range 0.22-1.32/patient/year). While open surgery has decreased over the last decade and PCNL has been stable, there seems to be a rise of RIRS during this period. Patients with cystine stones need periodic interventions for stone recurrences despite medical management, with limited data showing the impact on renal function. While the management is individualised, wide variability exists with often poor and incomplete patient data.

A novel screening method for potential naringinase-producing microorganisms

Naringinase has high industrial importance, and the progress in naringinase research is still quite slow. The unavailability of an effective, simple screening method, which will be applicable to different microorganisms such as bacteria, fungi, and actinomycetes, is one of the main reasons for this gap. Therefore, a simple plate assay was developed for effective screening of microorganisms for naringinase by exposing to iodine vapors. This plate assay will fill the technological void for simple screening method and will lead to screen more potent industrially important naringinase-producing microorganisms.

The Demographic Diversity of Food Intake and Prevalence of Kidney Stone Diseases in the Indian Continent

Food intake plays a pivotal role in human growth, constituting 45% of the global economy and wellbeing in general. The consumption of a balanced diet is essential for overall good health, and a lack of equilibrium can lead to malnutrition, prenatal death, obesity, osteoporosis and bone fractures, coronary heart diseases (CHD), idiopathic hypercalciuria, diabetes, and many other conditions. CHD, osteoporosis, malnutrition, and obesity are extensively discussed in the literature, although there are fragmented findings in the realm of kidney stone diseases (KSD) and their correlation with food intake. KSD associated with hematuria and renal failure poses an increasing threat to healthcare infrastructures and the global economy, and its emergence in the Indian population is being linked to multi-factorial urological disorder resulting from several factors. In this realm, epidemiological, biochemical, and macroeconomic situations have been the focus of research, even though food intake is also of paramount importance. Hence, in this article, we review the corollary associations with the consumption of diverse foods and the role that these play in KSD in an Indian context.

The potential effects of dietary food and beverage intakes on the risk of kidney stone formation

ABSTRACT Objective To determine the effect of nutritional habits on kidney stone formation and recurrence. Methods This study was conducted on 44 healthy individuals and 44 patients diagnosed with nephrolithiasis and aging between 20 and 65 years. Participants shared their salt consumption habits, daily fluid consumption amounts and general information about themselves in a questionnaire form. In addition, food and beverage consumption frequencies of participants were recorded through a food frequency questionnaire. Results Salt consumption frequencies of patients are higher than that of healthy individuals in both genders (p<0.05). It was found out that male individuals in the patient group salt dishes without tasting more frequently (p<0.05). Daily total water consumption of both genders in patient group is lower than that of healthy individuals (p<0.05). Meat consumption of male patients (51.6±31.35g/day) was found to be higher than that of healthy group (34.1±22.58g/day) (p<0.05). Additionally, individuals in the patient group consume less stinging nettle, corn, plum, loquat, orange juice and lemonade than healthy individuals (p<0.05). Conclusion Results of the study showed that total fluid intake, salt consumption habits, and vegetable, fruit and beverage consumption may be correlated with stone formation risk and nutrition habits may affect stone recurrence.

Perceptions of dietary factors promoting and preventing nephrolithiasis: a cross-sectional survey

OBJECTIVE

To assess knowledge of both promoting and preventive dietary factors on nephrolithiasis in a diverse patient population. Precipitating factors of kidney stone disease include diet, lifestyle, socioeconomic status, and race/ethnicity. However, patient awareness of these influences is poorly described.

MATERIALS AND METHODS

A 24-question survey, assessing intake-related risk factors for stone disease, was administered prospectively to 1018 patients. Responses were summarized with frequency and percent. Statistical comparisons were made using a propensity scoring method in order to account for potential confounding variables. Propensity scores were stratified into quintiles. Further analysis with multiple imputation was performed to account for any missing data in the survey. The results of the propensity-adjusted log-binomial regression model are presented as prevalence ratios (PRs) and 95% confidence intervals (CIs).

RESULTS

Respondents demonstrated limited knowledge of nutrient factors that influence stone development. However, most study participants (70.3%) reported a willingness to make lifestyle changes aimed at lowering their risk for stone disease. Respondents reporting previous nephrolithiasis education were less likely to report that diet had no effect on kidney stone formation (PR = 0.795, 95% CI 0.65, 0.96, p = 0.01) The type of physician who counseled the respondent had no association with patient knowledge for stone disease (PR = 0.83, 95% CI 0.63, 1.10, p = 0.2).

CONCLUSIONS

Knowledge of diet-related risk factors for nephrolithiasis is limited among this population. Respondents who received prior education appeared to maintain the knowledge of dietary risk for nephrolithiasis. Participants also expressed a willingness to make requisite dietary changes if that information is provided. Given that most stone formers experience a recurrence, these findings highlight the need for more comprehensive patient education strategies on the modifiable risk factors for nephrolithiasis.

A Comparison of Metoclopramide and Ondansetron Efficacy for the Prevention of Nausea and Vomiting In Patients Suffered From Renal Colic

BACKGROUND:

Renal stones are the third common disease of the urinary system after infections and diseases of the prostate. One of the most common manifestations of this disease after acute pain is nausea and vomiting.

AIM:

To compare the efficacy of metoclopramide and ondansetron in improving nausea and vomiting in patients referred to the emergency department with a chief complaint of nausea and vomiting.

METHODS:

This randomised double-blind clinical trial was conducted on patients referred to the emergency department of Vali-e Asr Hospital. Mg5 intravenous morphine and ketorolac ampoule were injected to control renal colic. Then, patients were randomly divided into two groups. Group 1 consisted of 90 subjects receiving 10 mg intravenous metoclopramide and group 2 including 90 subjects receiving 4 mg intravenous ondansetron. Vital signs were also measured and recorded.

RESULTS:

The mean and standard deviation of nausea in 0, 15, 30, 45, 60 and 120 minutes showed no significant difference between the two groups. Mean and standard deviation of vomiting at 0 minutes showed no significant difference between the two groups, but the remaining minutes, 15, 30, 45, 60 and 120, exhibited significant difference as a comparison of two groups, indicating that vomiting in the metoclopramide group was higher than ondansetron group.

CONCLUSION:

Our findings indicated that ondansetron was more effective than metoclopramide in preventing and improving vomiting in patients referred to emergency renal colic, where can be used with more efficacy and more acceptable side effects to improve nausea and vomiting.

Uric acid stones, clinical manifestations and therapeutic considerations

Uric acid stones account for 10%-15% of all urinary stones. Changes in dietary habits, environment or both can result in the increase of uric acid stones. The formation of uric acid stones is related to hyperuricosuria, low urinary volume and persistently low urinary pH. Diabetes and obesity also significantly increase the risk of stone formation. Dual-energy CT provides a convenient and reliable method for diagnosis. Stone composition analysis and 24-hour urine metabolic evaluations should be considered for further evaluation. Most small uric acid stones (diameter <2 cm) can be treated by pharmacotherapy or extracorporeal shock wave lithotripsy. However, ureteroscopy and other minimally invasive procedures should be reserved for larger stones (diameter ≥2 cm), or patients with concomitant urinary tract obstruction and/or infections. Additionally, adjustment of potential pathophysiologic defects by pharmacotherapy and dietary modification is strongly recommended for the prevention of uric stone recurrence.

Epidemiology, pathophysiology, and management of uric acid urolithiasis: A narrative review

An in-depth comprehension of the epidemiology as well as pathophysiology of uric acid urolithiasis is important for the identification, treatment, and prophylaxis of calculi in these patients. Persistently low urinary pH, hyperuricosuria, and low urinary volume are the most important factors in pathogenesis of uric acid urolithiasis. Other various causes of calculus formation comprises of chronic diarrhea, renal hyperuricosuria, insulin resistance, primary gout, extra purine in the diet, neoplastic syndromes, and congenital hyperuricemia. Non-contrast-enhanced computed tomography is the radiologic modality of choice for early assessment of patients with renal colic. Excluding situations where there is acute obstruction, rising blood chemistry, severe infection, or unresolved pain, the initial management ought to be medical dissolution by oral chemolysis since this method has proved to be effective in most of the cases.